title: The trend of macrolide resistance and emm types of group A streptococci from children at a medical center in southern Taiwan.
abstract: BACKGROUND
  Group A streptococcus (GAS) is a common pathogen in children. Macrolide resistance in GAS has been described worldwide. The aims of this study are to analyze macrolide resistance of GAS isolates in southern Taiwan and to clarify the relationship of emm typing and macrolide resistance in the past decade.
  
  
  METHODS
  All GAS isolated from patients younger than 18 years at a single tertiary center in southern Taiwan were collected from 2000 to 2012. Antibiotics susceptibility to erythromycin, azithromycin, and clindamycin were determined by agar dilution method, and were interpreted by Clinical and Laboratory Standards Institute (CLSI) standards. emm typing was performed by polymerase chain reaction (PCR).
  
  
  RESULTS
  A total of 301 isolates were collected during the period of 13 years. Scarlet fever (38.5%) and acute pharyngitis (32.2%) were the most common diagnosis. Decreased resistance rate of erythromycin from 53.1% in 2000 to 0% in 2010 was found, but it increased rapidly to 65% in 2011. The resistance rate of azithromycin was the lowest (4.2%) in 2005, but was higher than 15% after 2006. The involvement of the erythromycin resistance genes were mefA (53.1%), ermB (35.9%), and ermTR (10.9%). The resistance of clindamycin also increased since 2011. emm12 was the most common serotype and accounted for 44.9% of all isolates. Compared with the non-emm12 group, resistance to erythromycin, azithromycin, and clindamycin were more frequently detected in the emm12 group.
  
  
  CONCLUSIONS
  Increased resistance of GAS to macrolide and clindamycin was found in recent years. emm12 was the main serotype for macrolide resistance.
authors.affiliation: Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Po-Kai
authors.initials: PK
authors.lastname: Chuang
authors.affiliation: Department of Emergency Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Shih-Min
authors.initials: SM
authors.lastname: Wang
authors.affiliation: Centers for Disease Control, Fifth Branch, Kaohsiung, Taiwan.
authors.forename: Hui-Chen
authors.initials: HC
authors.lastname: Lin
authors.affiliation: Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yu-Hao
authors.initials: YH
authors.lastname: Cho
authors.affiliation: Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Yun-Ju
authors.initials: YJ
authors.lastname: Ma
authors.affiliation: Department of Emergency Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Tzong-Shiann
authors.initials: TS
authors.lastname: Ho
authors.affiliation: Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Ching-Fen
authors.initials: CF
authors.lastname: Shen
authors.affiliation: Department of Pediatrics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center of Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan. Electronic address: liucc@mail.ncku.edu.tw.
authors.forename: Ching-Chuan
authors.initials: CC
authors.lastname: Liu
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000942:Antigens, Bacterial / Q000235:genetics*; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D002981:Clindamycin / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D005260:Female; D005838:Genotype; D060005:Genotyping Techniques; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018942:Macrolides / Q000494:pharmacology*; D008297:Male; D008826:Microbial Sensitivity Tests; D016133:Polymerase Chain Reaction; D013290:Streptococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D013297:Streptococcus pyogenes / Q000145:classification* / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D013624:Taiwan / Q000453:epidemiology; D062606:Tertiary Care Centers
chemical_list: D000900:Anti-Bacterial Agents; D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D018942:Macrolides; C014689:streptococcal M protein; D002981:Clindamycin
keywords: Clindamycin; Group A streptococcus; Macrolide resistance; emm type